Recent Physics results with the COMPASS Experiment

TL;DR

The COMPASS experiment reports initial results on polarized quark and gluon distributions, transverse spin structure, and pion properties, advancing understanding of nucleon structure and hadron physics.

Contribution

This paper presents the first physics results from COMPASS on polarized distribution functions, transverse spin effects, and pion polarizabilities, using innovative experimental techniques.

Findings

First measurements of polarized quark and gluon distributions

Insights into transverse spin structure of the nucleon

Initial data on pion polarizabilities and hadron resonances

Abstract

The COMPASS experiment has obtained first physics results in the field of polarized distribution functions for quarks and gluons using muon scattering off polarized deuterons. The analysis using open charm production and pairs of high $p_T$ hadrons is presented. We also have used a transversely polarized target to address transverse information for quarks inside the nucleon. In addition, a pilot run with incoming pions taken late 2004 will give first information on the pion polarizabilities and hadron resonances. The physics prospects from this run as well as from future data taking in this field are also outlined.